Electrical winding construction



Dec. 19, 1961 w. T. SUTTON, JR

ELECTRICAL WINDING CONSTRUCTION Filed Sept. 26, 1957 INVENTOR 11/4112? Z'Surroudie. ZIW

HAAQ

ATTORNEYS example, in the video amplifier of a television set.

1 the turns of the coil or coils.

3,014,190 ELECTRICAL WINDING CONSTRUCTION Walter T. Sutton, Jr., Lexington, Ky., assignor, by mesne assignments, to Nytronics, Inc., Phillipsburg, N.J., a corporation of New Jersey Filed Sept. 26, 1957, Ser. No. 686,356 Claims. (Cl. 336--92) This invention relates to an improved electrical coil and transformer construction, rendering the same particularly useful in the automatic assembly of such circuit components into circuit sub-assemblies, as into printed circuits. This particular invention embodies improvements over and modifications of the invention disclosed in copending application Serail No. 626,175, filed December 4, 1956, in the name of Bernard M. Gold smith.

It is an object of the invention to provide an improved construction of the character indicated.

It is another object to provide an improved electricalcoil circuit element which can be fabricated at substantially reduced cost.

It is a further object to provide an improved electricalcoil circuit-element construction which will meet the above objectives and yet provide greater inductance within given dimensional limitations.

It is a specific object to meet the above objects with constructions in which the prongs or leads relied upon for primary mounting support of the entire assembled circuit element may be integrally formed of the same Wire as the turns of the windings themselves.

It is a further specific object to provide improved means for accurately automatically positioning windings of the character indicated in their ultimately assembled position.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the foilowing specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

FIG. 1 is a vertical sectional view of a coil construction embodying my invention;

FIG. 2 is a bottom view of the assembly of FIG. 1, the section of FIG. 1 being indicated at 11 in FIG. 2;

FIG. 3 is an exploded view of a transformer construction embodying principles of the construction of FIGS. 1 and 2;

FIG. 4 is a view similar to FIG. 1, but illustrating a modification; and

FIGS. 5 and 6 are still further similar views showing further embodiments.

Briefly stated, my invention contemplates application to the construction of coils," transformers, chokes and the like for use in electronic circuit assemblies, as, for The invention features integral formation of the turns of. the electrical coil with the mounting leads or prongs, 'and for this purpose employs relatively heavy, stiff wire for The assembly is made rugged and adaptable to receive an adjustably positioned ing agent, such as an epoxy resin. In the present case, the invention teaches specific embodiments iniwhich the ends of the wires which are used for support of the assembly are, at one location or another, folded back along parts of the length thereof, for specific reinforcement purposes. I

In one form to be described, the folded portions project inwardly (i.e. toward the bottom end) of the plastic housing so as to define an accurate locating means whereby the coil assembly may be positioned in predetermined spaced relation with the bottom or closed end nited States Patent 0 'magnetic core by securing the same with a plastic bond- Patented Dec. 19, 1961 of the housing. In other forms, the folded portions of the coil ends project externally of the housing and serve to reinforce the mounting portion, or to accurately retain the coil in assembled relation with a closure member, or to provide a more convenient method of making hand-soldered connections when employed in manual (as distinguished from automated) circuit assembly.

In FIGS. 1 and 2 of the drawings, my invention is shown in application to a coil construction employing a winding 10 fully contained and permanently secured within a body or housing 12, which, for convenience in handling, is generally cylindrical, and which for unambiguous angular orientation, may be formed with an elongated locating rib or key 13 at one angular location. The winding 10 is developed from relative stiff and heavy insulated wire and is shown as a single layer of turns, the ends of which are so formed and trimmed as to project axially beyond the axial confines of the coil, as at 1415. Heavy plastic-coated copper magnet wire or Copper Weld (copper-sheathed steel wire) provides adequate winding wire, and the insulation may be a dipped coating of plastic.

The wire from which the winding 10 is formed is preferably so rugged that the projecting ends 1415 of the coil 10 may serve as the mounting pins, developing the substantial support for the entire finished structure, so that no soldering or other connection to separate mounting pins is necessary to integrate the circuit component into its ultimate chassis. For convenience in mounting, the leads 14-15 may be nail-pointed by conventional techniques, but I indicate my preference that nail pointing be effectively provided merely by dipping the lead ends into molten solder and slowly raising the same, thereby developing pointed ends in the manner of a stalactite. Also if desired, as for unambiguous mountings, and as illustrated in FIG. 2, the respective leads 1415 may be oriented within the coil assembly at non-uniformly spaced intervals, that is, spaced less than diametrically opposite (although diametrical spacing is shown in FIG. 2), and one of the leads (15) may be longer than the other (14) to facilitate automatic circuit-assembly insertion.

The body 12 for the coil may comprise a cup-shaped shell, preferably formed of suitable plastic, such as molded high-temperature nylon, fiber glass, polystyrene or the like. The body 12 is shown to comprise an innor tubular member or stem 16 and an outer tubular member 17, connected to each other at end closure 18, thereby defining a cup-shaped space or volume 19 within which the coil 10 is to be received. In the form shown, the open end of the housing 12 is closed by a plug or plate member 20 press-fitted within the skirt of the outer wall 17 and permanently held in place, as by thermally deforming the outer projecting end of the stem 16 into radially overlapping relation with the closure member 20, as indicated at 21. Various forms of closuredevice 20, including the one illustrated in FIG. 1, are described in greater detail in copending patent application Serial No. 715,377, filed February 14, 1958. I

For ease of assembly and for accurate angular location of the coil with respect to the ultimate keyed orientation determined by the key 13, I prefer that the closure member 20 shall be formed with a locating lug or ear 22 received within the recess on the inner side of the locating lug or key 13. Also, the closure member 20 may be formed with radial locating slots or openings 23 at various predetermined angular locations, for reception 6r the wire ends 14-15. The closure member 20 happens to be shown with four such locating slots 23, because, as will appear from the discussion in connection with FIG.

3, the invention is equallyapplicable to transformer constructions, and the same closure member 20 may serve to complete the assembly of a simple coil, as in FIG. 1, or of a transformer, as in FIG. 3.

The bore of the stem 16 is preferably formed with elongated ribs (not shown, but disclosed in greater detail in said Goldsmith application) whereby a threaded ferrite or the like core member 24 may be received in self-tapping relation therewith. The bore of core member 24 may be formed to receive a key, for adjustment of threaded advance, as will be understood.

In accordance with a feature of the invention, the wire ends 14-15 are provided with portions of overlap defined by folding elongated portions thereof over each other, and in the form of FIGS. 1 and 2, such folded over-lapping portions are defined primarily at the inner end of the assembly and serve the purpose of accurately spacing and locating the coil 19 with respect to the inner wall of the end closure 13. Thus, for the wire ends 14, there is a first stretch or length 26 extending directly from the exterior of the assembly all the way into direct abutment with the closure member 18 of the housing, and a second portion 27 is folded into overlapping relation therewith and is directly and integrally connected to the lower end of the coil 10. In like manner, the externally projecting portion of the lead end includes a first portion 28 extending all the way into direct contact with the inner end or bottom of the housing cup, and a second portion 29 folded into overlapping relation therewith and directly and integrally connected to the axially inner end of the coil 10.

It will be appreciated that by folding the otherwise straight lead ends '1415 in the manner indicated at 26-27 and 28-29, substantial reinforcement is afforded between the ends of the coil and the locations of direct abutment with the housing. This provides a convenient and extremely useful means of assuring accurate location of the coil within the housing upon automatic assembly of one of these parts to the other, and the reinforcement afforded by overlapping lengths of wire relieves any physical distortion loads on the coil itself.

It should be noted that the reason for preferring a displaced location of the coil 10 with respect to the closed end of the housing is that the core member 24 may be adequately received in the bore of the stem 16 at a location substantially removed from coupling with the flux developed by the coil. This affords a maximum range of coupling adjustment, as will be understood, and this range may be held to close tolerances by reason of the locating function achieved by the folded portions of the lead wires 26-27 and 2829.

In the arrangement of FIG. 3, I illustrate essentially the same construction as described for FIGS. 1 and 2, but in application to a transformer, the view in FIG. 3 being exploded so as to illustrate the separate formation of the respective parts. The container or housing 12 may be the same as described for FIG. 1, and therefore the same reference numerals are employed. Inner coil 10' may, except for the lead wire 14', be essentially as described for the coil 10, and therefore the same reference numerals are employed, but with primed notation. The other coil of the transformer is indicated at 30 and is shown to comprise a plurality of turns of the same kind of wire as employed for the coil 10, but of course on a slightly larger diameter such that concentric support for the coil 30 may be derived directly from the coil 10- when one is assembled to the other. The number of turns for the windings 10'--30 are shown to be different, and the ultimate assembled position of the coil 30 with reference to the coil 10' is suggested by dashed outlines 30.

Since the ultimate desired nested relation of the coil 30 involves a different spacing (than that of coil 10) from the bottom or inner end of the housing 12, I show the formation of folded locating parts 31--32 for the lead end 3334 of slightly greater length than for the corresponding portions 26-27 and 2829 of the coil 10'. The ultimate positions of the folded portions 3132 are indicated at 31' 2 in the center portion of FIG. 3, and are seen to be in the same plane as the corresponding locating parts for the coil 16?.

The turns of the winding 30 have been indicated as perferably deriving concentric support from the turns of the winding 10'. This will mean that the lower lead 14' for the inner winding must be initially formed straight (as indicated in solid outlines in FIG. 3) so that as' sembly of the coil 30 may be made over the coil 10' before ultimate deformation of the lead 14- into its permanent shape, indicated at 14" in dashed outline. When thus finally formed as shown at 14", such lead for the inner coil It) will correspond in all respects to the lead 14 folded at 2627 and described in FIG. 1, except of course that its offset from the coil It? must be sufficient to clear the outer diameter of the coil 39.

When fully assembled in the manner described for FIG. 1, both coils 30 will be accurately and positively located by the bottom 18 of the housing 12, and potting, bonding and other techniques may be employed to permanently secure the turns of both windings to each other and to one or both of the inner walls of the annular space 19. The same closure member 20 may be employed as described in FIG. 2, it being understood that each one of the separate leads to the respective windings 10'-30 is received in a different locating recess or slot 23 therein.

In the arrangement of FIG. 4, accurate location of the coil 40 within the container or housing 41 is achieved by direct reference of the coil to the closure member 20, being of the same general construction as described in connection with FIG. 2. The housing 41 may also be the same as described at 12 in FIG. 1, but I indicate my preference that the housing 41 be slightly different, principally in respect to provision of a step or counterbore 42 (for receiving closure 20) near the outer end of the skirt thereof. In all other respects, the housing may be the same, so that the coil 40 is directly received and centrally located on the coil form or stem 43, carried by the bottom or closed end of the housing. Accurate location is achieved by folding the outwardly projecting ends of the straight leads back to such an extent that the tip end of each lead directly abuts the outer face of the closure member 29. Thus, for the case of the projecting lead or mounting pin 44, a first length of straight axially projecting wire 45 is connected directly to the bottom end of the coil '40, and a second folded-back portion 46 overlaps the portion 45 and is sufliciently offset from the slot 23 as to abut and locate against the bottom surface of the closure member 20. Similarly, for the case of the lead or mounting pin 47, a first length 48 of the wire is directly connected with the inner or far end of the coil 40, and a second length 49 overlaps the same and is of such length as to provide locating engagement with the bottom surface of the closure member 20.

In the arrangement of FIG. 5, I illustrate that the principles of my invention afford a means whereby such mutual reinforcement is derived from the folded portions of the lead wires that sufficient strength for mounting the entire assembly by such means may be achieved for wires of lesser gage than contemplated for arrangements as in FIGS. 1 and 3, wherein only a single thickness or length of coil wire is employed to derive the full support of the coil. This means that a substantially smaller gage wire may be employed for the turns of the coil, and the reinforcement afforded by doubling over and suitably anchoring the lead ends provides all the necessary supporting strength for the entire assembly; by reducing the size of the wire, the number of turns within a given volume may be increased, and therefore the range of inductances for which coil assemblies and transformer assemblies of the same general type may be provided within the same housing shape (i.e. range of turns, per unit volume) is very substantially extended. It is important to maintain the same housing shape, because for any automated circuit assembly, the same handling devices may then be employed for a greater variety of inductance or transformer elements.

In the arrangement of FIG. 5, the bottom locating principle for the coil 50 resembles that described in connection with FIGS. 1 and 2. Thus, the lead ends of the wire of coil 50 are first doubled back at 51152 to provide locating abutments with the bottom 53 of the housing 54. Theouter projecting ends of these same lead wires define the mounting prongs 5556, and as indicated (for reinforcement purposes), each of these prongs is defined by adjacent double-overlapped portions of the same wire. In the case of the prong 55, the folded-back length 57 extends substantially within the inner volume of the housing 54, and for the case of the prong 56, the doubled-back portion 58 similarly extends well within the housing 54. As indicated in connection with FIG. 1, I prefer to provide nail-pointed ends (55'--56') by dipping the mounting pins in solder as a final manufacturing step; this will mean that the double-overlapping wires defining each of the prongs 55-56 are solidly secured to each other over the outwardly projecting ends thereof, so that mutual reinforcement is a maximum, meaning that the smallest possible gage wire may be employed to derive adequate supporting strength for the entire assembly. As indicated also in connection with FIGS. 1 and 2, the coil 50 is preferably potted or otherwise permanently bonded to its supporting stem 59, and the same potting or bonding operation preferably also secures the interior folded portion of the leads 55-56 to each other and to the interior of the housing 54. Permanent bonding may be achieved by solid pot-ting, as exemplified in the said Goldsmith application, whereas partial potting is exempli tied in Goldsmith-Sutton pending application Serial No. 716,106, filed February 19, '1958; cross hatching for pot ting has been eliminated in the present drawings, for sake of clarity.

In the arrangement of FIG. 6, the prong support at 55'--56 is essentially the same as described for FIG. 5, meaning that the smaller-gage wire may be employed for the coil 50 because the outer projecting ends of the leads defining the prongs 5556' are folded back along each other; and again, the folded or doubled prong parts are I preferably soldered for reinforcement. The method of locating the coil 50 within the housing 54 is, however, of the general form illustrated in FIG. 4, coil location being referenced against the closure member 20, seated against the step or counterbore 42' in the housing 54'. One important difference is, however, to be noted in that the folded-back length 57 for the prong 55 extends within the inner volume of the housing, and the corresponding folded-back length 58' for the prong 56' also extends substantially inwardly of the housing. This is for the purpose of providing better anchorage for each of the prongs 55'56 within the potted plastic which securely bonds the lead portions 57'58 to an inner wall of the housing and to adjacent turns of the coil 50'; the potting may be provided only to the extent necessary to bond coil 50' to stem 59', and to securely bond the inner lead positions 57'58 at the lower lead of the assembly (i.e. to coil 50', to closure 20, and to the open or lower end of the housing skirt 54'), but in the form shown, a solid or full potting 60 is employed.

The description in connection with FIGS. 4, and 6 has been for the case of single coils merely to illustrate the general principle, as in the manner discussed in connection with FIGS. 1 and 2. It will be understood, however, that the same construction and description are equally applicable for transformers of the nature described in FIG. 3, and that the same wire-forming and coil-locating techniques are applicable in every case.

It will be seen that I have described an improved coil and transformer construction, lending itself in particular to mass-production of precision electrical components which are to be automatically assembled into an ultimate circuit, as into a printed circuit. My constructions afi'ord reinforcement at important parts of the assembly without destroying or in any way impairing electrical performance. In fact, certain of the forms, particularly of FIGS. 5 and 6, provide a means whereby very substantially increased inductance may be achieved within given space limitations, without in any way sacrificing the degree of security with which the prongs or mounting pins support the entire structure. For forms in which the exposed lead ends are doubled-over, as in FIGS. 4, 5, and 6, the lead becomes effectively a rectangular lug, thus facilitating Wiring connections, for manually wired situations. In every case, the wire from which the coil is formed is integrally formed with the mounting prong, and no separate connections are necessary.

While I have described the invention in detail for the preferred forms shown, it will be understood that modifications may be made within the scope of the invention as described in the claims which follow.

I claim:

1. In combination, a cylindrical plastic body containing an electrical winding concentrically supported there- Within, said winding being formed of relatively heavy wire and having ends projecting in angularly spaced relation beyond one end of said body and substantially parallel to the axis thereof, thereby defining integral lead connections, said wire being of suificiently strong material and size that said lead connections provide the substantial mounting support for said body, a portion of one of said ends of said wire being folded back along the length thereof to serve as a stop for axially locating said winding in said body.

2. The combination according to claim 1, in which said body is generally cup-shaped with a bottom closing one end of the body space within which said windings are accommodated, the folded portions of said one wire end being at the inner end of said body and projecting for contact with the closed end of said body to serve as a stop for axially locating said winding in said body.

3. In combination, a cylindrical plastic body, and an electrical coil of relatively heavy and stiff wire deriving concentric support from direct contact with said body in the interior thereof, said body being closed at one end and open at the other, one end of said coil being straight and integrally formed to extend axially with a portion projecting axially beyond the axial end of said body member, the other end of said coil being straight and integrally formed to extend axially with a portion adjacent the un supported radial side of said coil and with a portion projecting axially beyond the axial end of said body member at a location angularly spaced from said first projecting end, portions of said axially extending parts of said coil ends being folded into overlapping relation to serve as a stop for axially locating said coil in said body.

4. The combination of claim 3, in which the folded portion of at least one of said coil ends is at the inner end of said body and defines a portion projecting axially for direct locating contact with said inner end, whereby said coil is accurately axially located within said body and with respect to said inner end.

5. The combination of claim 3, in which the folded portions of said wire extend over the region of overlap with the turns of said coil, and in which said coil at said region of overlap is potted to said body and to the folded portions of said wire.

6. In combination, a plastic coil-supporting body member comprising a cup-shaped housing and an interior mounting stem supported by the closed end of said housing and defining a generally annular space between said stem and the inner wall of said housing, an electrical winding beyond the axial end of said body member, said ends being also folded back over portions of the length thereof and defining a reinforced portion for each end of said winding projecting axially toward the inner end of said housing for direct contact therewith so as to accurately locate said winding within said housing.

7. The combination as set forth in claim 1 including a second Winding substantially identical to said firstrnentioned winding and supported concentrically therewith within said body.

8. The combination of claim 3, in which the folded portions of said wire are at the extreme outwardly projecting ends thereof for serving as the axially locating stop.

9. The combination as set forth in claim 1 wherein said folded portion being beyond said one end of said body and for a length such that the tip end for each folded-back portion serves to axially locate said winding relative to said body.

10. The combination as set forth in claim 1 including closure means closing 01f said one end of said body about the ends of said winding with the projecting ends of said winding extending beyond said closure means, the ends of said wire being folded back over each other for an extent including not only that portion of the ends which project beyond the open end of said housing, but also a portion in overlapping relation with said coil, and means potting both said coil and the overlapped portion of said Wires within said housing, whereby the terminals defined by the externally projecting portions of said wire may be firmly referenced to said housing via said potting to serve as axially locating means for said coil relative to said housing.

References ited in the file of this patent UNITED STATES PATENTS 1,763,115 Wermine June 10, 1930 2,751,563 Willyard June 19, 1956 2,761,891 Violette Sept. 4, 1956 2,829,426 Franklin Apr. 8, 1958 2,836,805 Goldsmith May 27, 1958 2,889,524 Schmitz June 2, 1959 

